Index en-passant zobrist keys by file
authorMarco Costalba <mcostalba@gmail.com>
Sun, 19 Feb 2012 10:28:42 +0000 (11:28 +0100)
committerMarco Costalba <mcostalba@gmail.com>
Sun, 19 Feb 2012 10:31:36 +0000 (11:31 +0100)
commitec5b9994b55a32e0f8d8c6d9684c0f5fc0e4992a
tree5b57550cb4accb9dfe6a5df8c8662b43d29a72f1
parent3441e0075decb1acd8d3b4020b7822f743613124
Index en-passant zobrist keys by file

Instead of by square. This is a more conventional
approach, as reported also in:

http://chessprogramming.wikispaces.com/Zobrist+Hashing

We shrink zobEp[] from 64 to 8 keys at the cost of an extra
'and 7' at runtime to get the file out of the ep square.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
src/position.cpp
src/position.h